The second and third picture is very early 1960 version. Dad had one, I broke the cord end on the tool around 1970. Tried to glue back together, it was toast. Its made of Bakelite material. The first and last picture may be 1950's if I had to guess.

Dropped an old (seized) version Granddad had, the Bakelite shattered like glass. My current production (two speed corded) one is already giving my trouble after two years, and I might use it 4 times a year. I may try a different brand of rotary tool this time.